Device and method for measuring vaporization-melt ratio

ABSTRACT

A detection device for measuring the vaporization-melt ratio, the device including a light source, a first and second optical lens group, a slit, a first and second steering minor, a first and second primary minor, a glass containers, an object, a colored blade, and a high-speed recording analyzer. The first and second primary mirror is symmetrically placed at both ends of the glass container. The first optical lens group is located between the light source and the slit. The second optical lens group is located between the colored blade and the high-speed recording analyzer. The first steering mirror is installed behind the slit, passing the light through the slit to the first primary mirror. The light reflected by the second primary mirror is passed to the colored blade through the second steering minor located between the second primary minor and the colored blade.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of International Patent Application No. PCT/CN2010/077693 with an international filing date of Oct. 13, 2010, designating the United States, now pending, and further claims priority benefits to Chinese Patent Application No. 200910308292.4 filed Oct. 15, 2009. The contents of all of the aforementioned applications, including any intervening amendments thereto, are incorporated herein by reference.

CORRESPONDENCE ADDRESS

Inquiries from the public to applicants or assignees concerning this document should be directed to: MATTHIAS SCHOLL P. C., ATTN.: DR. MATTHIAS SCHOLL ESQ., 14781 MEMORIAL DRIVE, SUITE 1319, HOUSTON, Tex. 77079.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to the field of precision machining technology, and more particularly to a device and method for measuring of the vaporization-melt ratio in laser processing.

2. Description of the Related Art

The outline size of high-performance slit array antenna panels made of aluminum alloy in aerospace aircraft radar, missile antenna, and ship navigation system can reach 100-600 mm, while the thickness thereof is only 0.3-0.4 mm This requires processing many rectangular narrow slits in different directions to form a slit array, with the gap width of 0.1-0.3 mm The dimensional and shape accuracy is required to be 0.1-1 μm, the machined surface quality Ra <1.6 μm, and no microscopic burrs and flash. It is similar to the stainless steel high-density porous filter plates applied in petroleum and chemical industry for fluid purification, with the size of 80-200 mm and thickness of 0.5-2 mm Furthermore, a large number of tiny and high-density distributions of porosity shaped circular, rectangular or even profiled are required. The pore size is 0.1-0.3 mm, limited by the ratio depth and diameter, leading to restriction of thickness design. In addition, carbide nozzle of the spinneret, dusting and inkjet used in the textile, light industry, printing and other industries, the outline size of 10-100 mm, pore size 0.1-0.3 mm, and nozzle wall thickness 0.1-0.3 mm Thus, it is urgent to develop an efficient and high-quality precise machining method for preparation of medical micro fluidic chip and its mold production of stainless steel micro-flow channel.

The structure of the above-mentioned precise sheets is characterized with fine structure of hole, complex and different shape, dense and small size of slit and thin-walled structure. It belongs to the sheet of larger ratio between outline size and thickness. The machining dimensional accuracy, shape accuracy and surface quality are required to a high level. The special alloy and other metal materials of high thermal conductivity cause mechanical and thermal deformation of thin-walled precision sheet metal parts during processing. Limited to the size of tools, the cutting performance of small hole and seam processing is relatively poor. Traditional processing methods are difficult to meet the requirements of high precision, quality, and efficiency.

Because of the direct impact of vaporization-melt ratio on the precision and quality in laser precise machining, it is of important theoretical significance and application value to research and develop an apparatus and method of vaporization-melt ratio detection in laser processing.

SUMMARY OF THE INVENTION

The invention aims to solve the technical problems of processing a high-performance slit array antenna panel made of aluminum alloy in the fields of aerospace vehicles radar, missile antenna, and ship navigation system. The weight of the material removal during gasification is calculated by identifying the form of removal vapors, collecting the flowing information, considering the refractive index change and distribution characteristics based on the relationship between the refractive index and density in the transmission of the beam, and quantitatively analyzing the form of gasification at different times. The weight of the sample and molten removal is accurately weighed before and after processing, in order to get the weight of vapors and isolates. It needs to research the influence on the vaporization-melt ratio by laser energy input, further providing the experimental and theoretical base of impact on processing size, accuracy and surface quality.

The light is passed through the slit, steering minor, and primary mirror of optical lens group, radiating on an object D placed in the light and breathable glass containers. The state signals of vapors resulted from the processing is spread to the high-speed recording analyzer through the primary minor, steering mirror, and colored blade. The vaporization-melt ratio is calculated by analyzing the state information of gasification at different moments assisted with precision weighing.

To achieve the above objective, in accordance with one embodiment of the invention, there is provided a device for measuring vaporization-melt ratio in laser processing comprising a light source, a first optical lens group and a second optical lens group, a slit, a first steering minor and a second steering minor, a first primary minor and a second primary mirror, a glass containers, an electronic weighing instrument, a colored blade, and a high-speed recording analyzer. The first and second primary minor and is symmetrically placed at both ends of the glass container. The first optical lens group is located between the light source and the slit. The second optical lens group is located between the colored blade and the high-speed recording analyzer. The first steering mirror is installed behind the slit, passing the light through the slit to the first primary mirror. The light reflected by the second primary mirror is passed to the colored blade through the second steering minor located between the second primary minor and the colored blade. The light source is a krypton lamp, of which the light is passed to the slit by the first optical lens group. The light is passed to the first primary minor by the first steering minor. The light source is detected by the first primary minor and shines on the object D in the glass container. The optical phenomena of irradiation are recorded. The detection signal of vapors is passed through the second steering minor and the colored blade by the second primary minor to the high-speed recording analyzer. Finally, the vaporization-melt ratio of processing vapors is calculated by the analysis of the status of different moments.

A method for measuring of the vaporization-melt ratio in laser processing using the detection device comprises the steps of:

-   -   1) generating vapors in the laser processing; based on the         optical schlieren measurement principle of vapors, detecting the         refractive index change after the light passing through the         flows, identifying the form of vapors and density variations,         calculating the density distribution of gasification in         different moments according to the Gladstone-Dale gaseous         equation to obtain the weight of the vapors of different times;         and

2) accurately weighing the weight of work-piece before and after the entire laser processing using a higher-resolution weighing method; carefully collecting and weighing molten isolates in the glass container to get the weight of the vapors and the molten isolates and the vaporization-melt ratio; for homogeneous materials, excluding the weight of particles stripped directly away from the substrate, and measuring the vaporization-melt ratio; for uneven materials, collecting the particles stripped from the substrate and weighting the weight thereof to eliminate the affection of stripping particles, whereby obtaining an amended accurate ratio between gasification and melting weight; for melting recasts, detecting the volume of recast layer based on image processing to eliminate the effects on the weight of material removal by metallographic analysis, whereby getting a precise vaporization-melt ratio.

Advantages of the invention are summarized below. Using the vaporization-melt ratio detection device and method to effectively grasp the interactive status and conditions between laser and material, to meet the requirement of high-quality removing of processing products through analysis and control of the ratio between gasification and melt in processing zone. It is an effective way to process the smaller size of the tiny structures to improve the precision and quality during the laser forming and manufacturing for breaking through the original processing equipments and quality indicators. Processing a variety of materials of cavity and structural parts such as 0.05-0.2 mm sized tiny holes with the depth-to-diameter ratio of 20:1 solves technical problems of filter structure in the fields of radar antenna panels' textiles, petroleum, and chemical industry. To meet the technical requirements of micro-structural parts, it need to improve the precision and quality of laser processing by an order of magnitude to solve processing problems of the tiny plastic mold groove cavity, comprising size, shape, position accuracy and quality requirements.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described hereinbelow with reference to accompanying drawings, in which the sole figure is a schematic diagram of a detection device of vaporization-melt ratio in laser processing in accordance with one embodiment of the invention.

In the drawings, the following reference numbers are used: 1. light source; 2. first optical lens group; 3. slit; 4. first steering minor; 5. first primary minor; 6. laser head; 7. glass container; 8. electronic weighing instrument; 9. second primary minor; D. object; 10. second steering minor; 11. colored blade; 12. second optical lens group; 13. high-speed recording analyzer.

DETAILED DESCRIPTION OF THE EMBODIMENTS

For further illustrating the invention, experiments detailing a device and method for measuring of the vaporization-melt ratio in laser processing are described below. It should be noted that the following examples are intended to describe and not to limit the invention.

As shown in the figure, a detection device for vaporization-melt ratio in laser processing comprises a light source 1, a first optical lens group 2 and a second optical lens group 12, a slit 3, a first steering mirror 4 and a second steering minor 10, a first primary mirror 5 and a second primary minor 9, a glass containers 7, an electronic weighing instrument 8, an object D, a colored blade 11, and a high-speed recording analyzer 13. The first and second primary minor 5 and 9 is symmetrically placed at both ends of the glass container 7. The first optical lens group 2 is located between the light source 1 and the slit 3. The second optical lens group 12 is located between the colored blade 11 and the high-speed recording analyzer 13. The first steering mirror 4 is installed behind the slit 3, passing the light through the slit 3 to the first primary mirror 5. The light reflected by the second primary minor 9 is passed to the colored blade 11 through the second steering mirror 10 located between the second primary minor 9 and the colored blade 11. The light source 1 is a krypton lamp, of which the light is passed to the slit 3 by the first optical lens group 2. The light is passed to the first primary minor 5 by the first steering minor 4. The light source 1 is detected by the first primary minor 5 and shines on the object D in the glass container. The optical phenomena of irradiation are recorded. The detection signal of vapors is passed through the second steering minor 10 and the colored blade 11 by the second primary minor 9 to the high-speed recording analyzer 13. Finally, the vaporization-melt ratio of processing vapors is calculated by the analysis of the status of different moments.

The detection device is placed on a laser processing machine. Laser beam from the laser head 6 through the upper window radiates on the object D in the glass container 7. Meanwhile, the processing vapors are radiated by the detection light from the light source 1 passing through the right window of the glass container 7. The status information of vapors is passed out from the left window of the glass container 7 through the second primary mirror 9, the second steering minor 10, and the colored blade 11, finally collected, recorded, and analyzed by a high-speed recording analyzer 13. The glass container 7 as a transparent and breathable device allows vapors to escape at any time. The state of vapors is collected, recorded, and analyzed by the high-speed recording analyzer during the whole processing. The detailed implementation is demonstrated as follows.

The laser processing of 50 g slit array antenna panel is taken as an example. When the vapors are radiated by the detection light, based on the optical schlieren measurement principle of vapors, detecting the refractive index change after the light passing through the flows, identifying the form of vapors and density variations, the density distribution of gasification in different moments is calculated according to the Gladstone-Dale gaseous equation. The weight of vapors is about 5 g. At the same time, the weight of work-piece before and after the entire laser processing is accurately weighed by precision weighing. Then the molten isolates in the glass container 7 are carefully collected and weighed by the electronic weighing instrument 8 to get the weight of the vapors and molten isolates, finally the vaporization-melt ratio. In this case, the weight of the vapors, that is, the difference of work-piece weight before and after laser processing, is about 5 g. On the other hand, the molten isolates are carefully collected and weighed of 5 g. So the total removal is 10 g during the processing, while the vaporization-melt ratio of 1. The vaporization-melt ratio is controlled by changing the laser energy input. For example, processing a total removal of 10 g, 8 g for the gasification, 2 g for the melt, the vaporization-melt ratio is 4. Obviously, the processing quality of value 4 is significantly an order of magnitude higher than that of value 1. For homogeneous materials, excluding the weight of particles stripped directly away from the substrate, the vaporization-melt ratio is measured by the above method. In comparison, for uneven material, the particles stripped from the substrate are collected to eliminate the affection of stripping particles. Similarly, it is available to get the weight of stripping particles and the total weight of material removal by using precise weighing method. After the correction, the accurate ratio between gasification and melting weight is obtained. For the melting recast by metallographic analysis, the volume of recast layer is detected based on image processing to eliminate the effects on the weight of material removal, getting precise vaporization-melt ratio. This method can be applied to laser cutting, milling, cladding, and other processing of vaporization-melt ratio detection.

While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention. 

1. A device for measuring vaporization-melt ratio, comprising: a) a light source (1); b) a first optical lens group (2); c) a second optical lens group (12); d) a slit (3); e) a first steering minor (4); f) a second steering minor (10); g) a first primary minor (5); h) a second primary minor (9); i) a glass container (7); j) a colored blade (11); k) a high-speed recording analyzer (13); and l) an electronic weighing instrument (8); wherein the first primary minor (5) and the second primary minor (9) are symmetrically placed at both ends of the glass container (7); the first optical lens group (2) is located between the light source (1) and the slit (3); the second optical lens group (12) is located between the colored blade (11) and the high-speed recording analyzer (13); the first steering minor (4) is installed behind the slit (3), passing the light through the slit (3) to the first primary minor (5); the second steering mirror (10) is located between the second primary minor (9) and the colored blade (11); the light reflected by the second primary minor (9) is passed to the colored blade (11) through the second steering mirror (10); the light source (1) is a krypton lamp, of which the light is passed to the slit (3) by the first optical lens group (2); the light is passed to the first primary mirror (5) by the first steering minor (4); the light source (1) is detected by the first primary minor (5) and shines on an object (d) in the glass container; the optical phenomena of irradiation are recorded; the detection signal of vapors is passed through the second steering minor (10) and the colored blade (11) by the second primary minor (9) to the high-speed recording analyzer (13); and the vaporization-melt ratio of processing vapors is calculated by the analysis of the status of different moments.
 2. A method for measuring of vaporization-melt ratio in laser processing using the device of claim 1, the method comprising the steps of: a) generating vapors in the laser processing; based on the optical schlieren measurement principle of vapors, detecting the refractive index change after the light passing through the flows, identifying the form of vapors and density variations, calculating the density distribution of gasification in different moments according to the Gladstone-Dale gaseous equation to obtain the weight of the vapors of different times; and b) accurately weighing the weight of work-piece before and after the entire laser processing using a higher-resolution weighing method; carefully collecting and weighing molten isolates in the glass container (6) to get the weight of the vapors and the molten isolates and the vaporization-melt ratio; for homogeneous materials, excluding the weight of particles stripped directly away from the substrate, and measuring the vaporization-melt ratio; for uneven materials, collecting the particles stripped from the substrate and weighting the weight thereof to eliminate the affection of stripping particles, whereby obtaining an amended accurate ratio between gasification and melting weight; for melting recasts, detecting the volume of recast layer based on image processing to eliminate the effects on the weight of material removal by metallographic analysis, whereby getting a precise vaporization-melt ratio. 